Iran's state television said the deal was struck on Monday, in talks between International Atomic Energy Agency (IAEA) head Yukiya Amano, and the Iranian nuclear chief, Ali Akbar Salehi.

For two years, the IAEA has trying to reach a deal with Iran to gain greater access to documents regarding the country’s nuclear program, in addition to related personnel and sites.

The sides agreed to a "roadmap'' that will give UN inspectors broader access to nuclear sites, including the heavy water reactor under construction at Arak, and a key uranium mine.

"The practical measures will be implemented in the next three months, starting from today," Amano said in a news conference in Tehran, broadcast on state television.

The IAEA has complained that Iran has restricted its access at some nuclear sites. Press reports said that the deal with Amano could improve the chances that Iran and the P5+1 world powers will be able to reach an agreement regarding its nuclear program, when negotiations resume next week.

The French foreign minister, Laurent Fabius, said on Monday he was hopeful a deal could be reached with Iran over its nuclear program, although Tehran still had “to make an effort” on a few points.

"We are not far from an agreement with the Iranians, but we are not there yet," Fabius told Europe 1 radio.